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We will not notice as we enjoy our daily lives that the cost of our neglect could soon cause the greatest tragedy in the memory of humankind.
Now consider Earth's climate history. These curves for global temperature, atmospheric CO2 and sea level were derived from ocean cores and Antarctic ice cores, from ocean sediments and snowflakes that piled up year after year over 800,000 years forming a two-mile thick ice sheet. As you see, there's a high correlation between temperature, CO2 and sea level. Careful examination shows that the temperature changes slightly lead the CO2 changes by a few centuries. Climate change deniers like to use this fact to confuse and trick the public by saying, "Look, the temperature causes CO2 to change, not vice versa." But that lag is exactly what is expected. Small changes in Earth’s orbit that occur over tens to hundreds of thousands of years alter the distribution of sunlight on Earth. When there is more sunlight at high latitudes in summer, ice sheets melt. Shrinking ice sheets make the planet darker, so it absorbs more sunlight and becomes warmer. A warmer ocean releases CO2. And more CO2 causes more warming, A self perpetuating cycle. So CO2, methane, and ice sheets were feedbacks that amplified global temperature change causing these ancient climate oscillations to be huge, even though the climate change was initiated by a very weak force.
The important point is that these same amplifying feedbacks will occur today. The physics does not change. As Earth warms, now because of extra CO2 we put in the atmosphere, ice will melt, and CO2 and methane will be released by warming ocean and melting permafrost. While we can't say exactly how fast these amplifying feedbacks will occur, it is certain they will occur, unless we stop the warming. There is evidence that feedbacks are already beginning. Precise measurements by GRACE, the gravity satellite, reveal that both Greenland and Antarctica are now losing mass, several hundred cubic kilometres per year. And the rate has accelerated since the measurements began nine years ago.
Imagine an asteroid on a direct collision course with earth
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